Detection Spray with a freshly prepared 200 g/l solution of phosphomolybdic acid R in ethanol (96 per cent) R and heat at 150c for 15 min; examine in daylight.

Results See below the sequence of the zones present in the chromatograms obtained with the reference solution and the test solution. Furthermore, other zones may be present in the chromatogram obtained with the test solution.

. Examine the chromatograms obtained in the test for chromatographic profile.

Results The characteristic peaks in the chromatogram obtained with the test solution are similar in retention time to those in the chromatogram obtained with the reference solution.

TESTS

Relative density (2.2.5)

0.961 to 0.975.

Refractive index (2.2.6)

1.528 to 1.539.

Optical rotation (2.2.7)

+ 10.0o to + 24.0o.

Chromatographic profile

Gas chromatography (2.2.28): use the normalisation procedure.

Test solution Dissolve 0.20 ml of the oil to be examined in heptane R and dilute to 10.0 ml with the same solvent.

Reference solution Dissolve 20 of pinene R, 20 of limonene R, 50 of fenchone R, 20 of estragole R, 100 of anethole R and 20 of anisaldehyde R in heptane R and dilute to 10.0 ml with the same solvent.

Column:

material: fused silica,

size: l = 60 m, = 0.25 mm,

stationary phase: macrogol 20 000 R (film thickness 0.25 ).

Carrier gas: helium for chromatography R.

Flow rate: 1 ml/min.

Split ratio: 1:200.

Temperature:

Detection Flame ionisation.

Injectionn1.0

Elution Order indicated in the composition of the reference solution. Record the retention times of these substances.

System suitability Reference solution:

resolution: minimum 5.0 between the peaks due to estragole and trans-anethole.

Using the retention times determined from the chromatogram obtained with the reference solution, locate the components of the reference solution on the chromatogram obtained with the test solution and locate cis-anethole using Figure 1826.-1. (Disregard the peak due to heptane).

Determine the percentage content of each of these components. The percentages are within the following ranges:

pinene: 1.0 per cent to 10.0 per cent,

limonene: 0.9 per cent to 5.0 per cent,

fenchone: 12.0 per cent to 25.0 per cent,

estragole: maximum 6.0 per cent,

cis-anethole: maximum 0.5 per cent,

trans-anethole: 55.0 per cent to 75.0 per cent,

anisaldehyde: maximum 2.0 per cent.

The ratio of -pinene content to limonene content is greater than 1.0.

STORAGE

In a well-filled, airtight container, protected from light and at a temperature not exceeding 25oC.